Yeasts trehalase from

Other inverting glucosidases which conform to the pattern of direct hydrolysis of glycosyl fluorides having the correct anomeric configuration, and transglycosylation with inversion if the anomeric configuration is opposite to that of the natural substrates are trehalase from rabbit renal cortex and from the yeast Candida tropicalis, and ) -D-xylosidase from Bacillus pu-milis. ... 

Secondly, there is an interaction of PolyP with polycationic activators. As for yeast trehalase, the inhibitory effect is probably due to the interactions with polyamines, which are activators of the enzyme (App and Holzer, 1985). PolyP inhibited trehalase from vegetative yeast cells and, to a lesser extent, that from the spores (Wolska-Mitaszko, 1997). 

B. Wolska-Mitaszko (1997). Trehalases from spores and vegetative cells of yeast Saccharomyces cerevisiae. J. Basic Microbiol., 37, 295-303. 

A convenient source of trehalase is bakers yeast. It is an a-n-glu-cosidase distinguishable from maltase by the damage suffered by the maltase on yeast storage. a,a-Trehalose added to bakers yeast is fermented (in aqueous suspension), but the a,a-trehalose stored within the yeast remains unaffected. Evidently, there is a spatial separation between yeast trehalase and its stored trehalose. The enzyme may be at the cell... 

The pH optimum for the fermentation of a,a-trehalose by living yeast differs from that of n-glucose fermentation, being narrow at a pH of about 5. This optimum coincides with that of brewers -yeast trehalase and indicates that hydrolytic splitting of the a,a-trehalose molecule may precede fermentation of a,a-trehalose. Bakers yeast trehalase is less stable than brewers yeast trehalase. Courtois and Valentino showed that the tetraaldehyde produced by the periodate oxidation of a,a-tre-halose is not attacked by trehalase. On the other hand, Helferich and Stryk showed that 6-0-(methylsulfonyl)-a,a-trehalose is attacked. Hydrolysis of a,a-trehalose by almond emulsin took place to the extent of 27%, and of the monomesyl ester to the extent of 15.5%, after 6,120 minutes. The corresponding figures for yeast extract were 12.1% and 8.3%, respectively, after 7,200 minutes. 

The pH optimum of trehalase varies according to its source. This was known for different yeasts at the time of Myrback s review. Frerejacque obtained material with trehalase activity from swine intestinal mucosa, beef liver, snail digestive Juice, and sheep small intestine, all preparations having a pH optimum of 6. 

An inactive form of aa-trehalase and its activating protein have been partly purified from resting cells of baker s yeast Saccharomyces) by a combination of fractional precipitation with ammonium sulphate and ion-exchange chromatography. For activation by adenosine 3, 5 -cyclic phosphate, this system appeared to depend on the presence of ATP and Co +, or Mg +, or Mn + cations. The activating protein lost some of its dependence on adenosine 3, 5 -cyclic phosphate during purification, and it may be a protein kinase activation of aa-trehalase would then be associated with phosphorylation of the kinase. 

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